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Zeta (z) Puppis


Shim1Pel.gif (799 bytes) z Puppis Shim1Pel.gif (799 bytes) Bayer designation (1603) Shim1Pel.gif (799 bytes)
Shim1Pel.gif (799 bytes) HR 3165 Shim1Pel.gif (799 bytes) Harvard Revised Photometry designation (1879+) Shim1Pel.gif (799 bytes)
Shim1Pel.gif (799 bytes) HD 66811 Shim1Pel.gif (799 bytes) Henry Draper Catalogue (1918+) Shim1Pel.gif (799 bytes)
Shim1Pel.gif (799 bytes) SAO 198752 Shim1Pel.gif (799 bytes) Smithsonian Astrophysical Observatory (1966+) Shim1Pel.gif (799 bytes)
Shim1Pel.gif (799 bytes) 39429 Shim1Pel.gif (799 bytes) Hipparcos catalogue (1997) Shim1Pel.gif (799 bytes)

Synopsis

Single star; early Of-type supergiant (O4I(n)f); located in Puppis; R.A. 08:03:35.052, dec. -40:00:11.64; culmination early March; magnitude 2.25; distance 429 pc (approx 1400 light years).

Description

Zeta Puppis is one of the best studied O-type stars; several important parameters have been determined with good accuracy, including the distance 352 (429) 549 pc (~ 1400 light years); diameter 20 R¤; effective temperature 42,000 ± 1500 K; and period of rotation ~4.8 – 5.2 days (Howarth et al. 1995, Schaerer et al. 1997).

The spectral type is certainly early O: Ochsenbien et al. 1988 published a value of O5Iaf; the earlier value of O4I(n)f derived by Walborn 1972 is preferred by Howarth et al. 1995 (table 1) and also by Schaerer et al. 1997.

 

 

[Howarth et al. 1995, table 1, quotes Teff = 42,000 ± 1500K from other sources, although their value for B-V, -0.27, suggests a somewhat lower temperature: around 32,500 K is typical for supergiants with this value of B-V. Böhm-Vitense 1989a, p. 59, gives a value of 30,700 ± 2500K for z Puppis. Schaerer et al. 1997 adopts the 42,000K value.]

Property Value Notes/References
R.A. 8:03:35.000  
Declination -40:00:11.64  
Precession in RA 21.100  
Precession in dec. -103.000  
Proper Motion RA -0.031 Includes cos(dec) term.
Proper Motion dec 0.011  
Radial Velocity -24.0 km/s  
Parallax 2.33±0.51 mas Schaerer et al. 1997
Distance 429 pc Schaerer et al. 1997
mv 2.25  
Mv -6.06 calculated with d=460 pc
M*/M¤ 59 Lamers & Cassinelli 1999
L*/L¤ 740,000
 
790,000
log L/L¤ = 5.74 (5.87) 6.02, Schaerer et al. 1997
Lamers & Cassinelli 1999
B-V -0.27  
U-B -1.09  
V-R -0.11  
R-I -0.22  
b-y -0.146  
m1 0.115  
c1 -0.198  
Hb 2.534  
Spectral Type O4I(n)f
O5Iaf
Howarth et al. 1995
Ochsenbien 1988
R/R¤ 20
14 (16.3) 21.7
17
Howarth et al. 1995
Schaerer et al. 1997
Lamers & Cassinelli 1999
Teff 30,700K
42,000K
42,400K
Böhm-Vitense 1989a
Howarth et al. 1995
Lamers & Cassinelli 1999
Rotational Velocity 211.000 km/s Howarth et al. 1995
Period 4.8-5.2 days Howarth et al. 1995
Table 1: Known Parameters for Zeta Puppis. (After Ochsenbein & Halbwachs 1987 except where otherwise noted.)

Discussion

Mass Loss

Mass loss is typical for hot luminous stars. For Zeta Puppis a mass loss rate was determined from radio data by Lamers and Leitherer and rescaled by Schaerer et al. (1997) to reflect their revised distance estimate, yielding log M-dot = -5.57 ± 0.15.

Zeta Puppis possibly belongs to the young Vela R2 association of stars (Sahu 1992, Schaerer et al. 1997).

Observation

Easily seen with the naked eye.

References

Böhm-Vitense, Erika (1989a): Introduction to Stellar Astrophysics. Volume 1 – Basic Stellar Observations and Data. Cambridge.

Howarth, Ian D.; Prinja, Raman K.; Massa, Derck (1995): The IUE MEGA Campaign: The Rotationally Modulated Wind of z Puppis.   The Astrophysical Journal, 452:L65-L68, 10 October 1995.

Lamers, Henny J.G.L.M.; Cassinelli, Joseph P. (1999): Introduction to Stellar Wind. Volume 3. Cambridge.

Ochsenbein F.; Halbwachs J.L. 1987: Le Catalogue des Etoiles les Plus Brillantes (Catalogue of the Brightest Stars). Bull. Inform. CDS 32, 83.  NASA Astronomical Data Centre, catalogue 5053A.

Sahu, M. (1992): Unpublished PhD thesis, cited in Schaerer et al. (1997).

Schaerer, Daniel; Schmutz, Werner; Grenon, Michel 1997: Fundamental Stellar Parameters of z Pup and g2 Vel from HIPPARCOS Data. ApJ Letters 484: L153-156.


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